Knee arthritis is a debilitating problem that is increasing in prevalence due to an aging population and an obesity epidemic in much of the world. In an arthritic knee, protective cartilage at a point of articulation between a femur and a tibia is often worn away, diseased or otherwise damaged, causing significant pain, discomfort, and disability for a human subject. In many cases, knee arthritis leads human subjects to seek knee replacement surgery, also referred as “knee arthroplasty.” Nearly 600,000 knee replacement surgeries are performed annually in the U.S. alone.
Knee arthroplasty involves replacing one or more worn, diseased or otherwise damaged knee joint surfaces with metal and/or plastic components shaped to allow natural motion of the knee. Knee replacement can be total or partial. Total knee replacement surgery, also referred to as total knee arthroplasty (“TKA”), involves a total replacement of a distal end of a femur, a proximal end of a tibia, and often an inner surface of a patella with prosthetic parts. Cuts are made on the distal end of the femur, the proximal end of the tibia, and optionally, the inner surface of the patella. Prosthetic parts are then attached to the cut surfaces. The prosthetic parts are intended to create a stable knee joint that moves through a normal range of motion. The replacement of knee structures with prosthetic parts can, if appropriately implanted, allow the knee to avoid bone-on-bone contact and provide smooth, well-aligned surfaces for joint movement.